A masked pro-Russian activist guards a barricade during a rally at the regional administration building that they had seized earlier in Donetsk, Ukraine, Thursday, April 10, 2014. in Donetsk, Ukraine, Thursday, April 10, 2014. Ukraineís acting president on Thursday promised pro-Russian activists occupying government buildings in the countryís east that they will not be prosecuted if they lay down their arms, as protests continue to flare up across Ukraineís industrial heartland. (AP Photo/Efrem Lukatsky)

This week’s ethnic Russian demonstrations in Eastern Ukraine, fist fights in the Ukrainian parliament, and the image of a country unraveling are all too predictable. They are right out of Vladimir Putin’s Crimea playbook from a month ago.

And just as in Crimea, we shouldn’t believe anything Moscow says about what it is doing. Putin aims to destabilize the heavily Russian-speaking eastern part of Ukraine to weaken confidence in the Kiev government and argue that Russia alone can bring about order.

Putin said Crimea would be his last territorial demand in the former Soviet space. But it is best with Putin not to listen to what he says but watch what he does. He massed thousands of troops on the Ukrainian border to intimidate its people and government.

As Secretary of State John Kerry argued this week, the Russian government sent in its own operatives to stir up protests in the big cities of eastern Ukraine’s industrial heartland — Donetsk, Kharkiv, Luhansk, and Dnepropetrovsk. Gangs of armed men seized Ukrainian government offices and alternatively pleaded for Russian help in organizing plebiscites to vote for freedom from Ukraine.

How should the United States and Europe respond? The problem President Barack Obama and German Chancellor Angela Merkel face is that Putin holds the far stronger hand in the poker match. He can act quickly and decisively without worrying about his rubber-stamp Duma and an approving Russian public. He has a plan — dominate and neutralize the countries around Russia to create a buffer zone from his adversaries, NATO and the European Union.

Obama and Merkel are playing a much weaker hand. They have wisely decided not to use their strongest card — NATO’s far stronger military — to counter Putin’s aggression. They are left with only two ways to slow him down.

First, their most effective potential leverage is the threat of major economic sanctions. Blocking Russian imports of Western manufactured goods or financial sanctions would hit the Russian economy hard and might give Putin pause. But Putin likely concludes Europe won’t agree on such tough sanctions. Too many European countries have substantial trade relations with Russia, especially in imports of Russian natural gas. Putin knows the relatively tougher U.S. and Canadian attitude toward Ukraine is not shared by Greece, Cyprus, Italy, and, more importantly, Germany. Absent transatlantic unity on sanctions, Putin may not fear the West’s sanctions card.

Second, the United States and NATO can be much stronger in responding to Putin. Obama can return to President George W. Bush’s missile defense proposal in Poland and the Czech Republic. NATO can move more military forces to the Baltics and Poland. And the United States and Europe should provide greater military assistance to Ukraine.

It was not a mistake, as some have argued, to expand NATO and the EU into Eastern Europe. It was a significant strategic advance for democracy and free market capitalism. Showing some backbone now is the surest way for the United States to protect NATO’s position in Eastern Europe as Putin respects one thing — power.

A suddenly aggressive Russia is now a major preoccupation of Obama’s presidency. With the increasing global perception of a weakening America as backdrop, the president will need to continue to draw a bright red line around the 26 European members of NATO, especially the Baltic states, to remind Putin of America’s Article V defense of alliance territory. Our allies, as well as Putin, are looking to see if Washington will display confidence, toughness and leadership in the most serious security crisis in Europe since the Cold War’s end.

Nicholas Burns is a professor of the practice of diplomacy and international politics at Harvard’s Kennedy School of Government.